Catheter-associated urinary tract infection (CAUTI) presents a significant health problem worldwide and is associated with increased morbidity and mortality. Herein, a silver-polytetrafluoroethylene (Ag-PTFE) nanocomposite coating for catheters was developed via a facile wet chemistry method. Benefiting from the synergistic effect of Ag and PTFE, the as-prepared Ag-PTFE-coated catheter exhibited enhanced antibacterial and antiadhesive activities against two CAUTI-associated strains: E. coli WT F1693 and S. aureus F1557. Compared to the uncoated commercial silicone catheters and the Ag-coated catheters, the Ag-PTFE-coated catheters were able to reduce bacterial adhesion by up to 60.3% and 55.2%, respectively. The Ag-PTFE-coated catheters also exhibited strong antibiofilm activity, reducing biofilm coverage by up to 97.4% compared with the commercial silicone catheters. In an in vitro bladder model, the Ag-PTFE-coated catheter displayed excellent anti-infection efficacy against bacteriuria, extending the lifetime of silicone catheters from a mean of 6 days to over 40 days. The Ag-PTFE coating also showed good biocompatibility with fibroblast cells in culture, making it a prospective strategy to overcome current challenges in CAUTI.

PurposeHydrogels with low viscosities tend to be difficult to use in constructing tissue engineering (TE) scaffolds used to replace or restore damaged tissue, due to the length of time it takes for final gelation to take place resulting in the scaffolds collapsing due to their mechanical instability. However, recent advances in rapid prototyping have allowed for a new technology called bioplotting to be developed, which aims to circumvent these inherent problems. This paper aims to present details of the process.Design/methodology/approachThe paper demonstrates how by using the bioplotting technique complex 3D geometrical scaffolds with accurate feature sizes and good pore definition can be fabriated for use as biological matrices. PEG gels containing the cell‐adhesive RGD peptide sequence were patterned using this method to produce layers of directional microchannels which have a functionalised bioactive surface. Seeding these gels with C2C12 myoblasts showed that the cells responded to the topographical features and aligned themselves along the direction of the channels.FindingsThis process allows plotting of various materials into a media bath containing material of similar rheological properties which can be used to both support the structure as it is dispensed and also to initiate cross‐linking of the hydrogel. By controlling concentrations, viscosity and the temperature of both the plotting material and the plotting media, the speed of the hydrogel gelation can be enhanced whilst it is cross‐linking in the media bath. TE scaffolds have been produced using a variety of materials including poly(ethylene glycol) (PEG), gelatin, alginic acid and agarose at various concentrations and viscosities.Originality/valueThis paper describes one of the very few examples of accurate construction of 3D biological microporous matrices using hydrogel material fabricated by the bioplotting technique. This demonstrates that this technique can be used to produce 3D scaffolds which promote tissue regeneration.

Ligaments and tendons have previously been tissue engineered. However, without the bone attachment, implantation of a tissue-engineered ligament would require it to be sutured to the remnant of the injured native tissue. Due to slow repair and remodeling, this would result in a chronically weak tissue that may never return to preinjury function. In contrast, orthopaedic autograft reconstruction of the ligament often uses a bone-to-bone technique for optimal repair. Since bone-to-bone repairs heal better than other methods, implantation of an artificial ligament should also occur from bone-to-bone. The aim of this study was to investigate the use of a poly(ethylene glycol) diacrylate (PEGDA) hydrogel incorporated with hydroxyapatite (HA) and the cell-adhesion peptide RGD (Arg-Gly-Asp) as a material for creating an in vitro tissue interface to engineer intact ligaments (i.e., bone-ligament-bone). Incorporation of HA into PEG hydrogels reduced the swelling ratio but increased mechanical strength and stiffness of the hydrogels. Further, HA addition increased the capacity for cell growth and interface formation. RGD incorporation increased the swelling ratio but decreased mechanical strength and stiffness of the material. Optimum levels of cell attachment were met using a combination of both HA and RGD, but this material had no better mechanical properties than PEG alone. Although adherence of the hydrogels containing HA was achieved, failure occurs at about 4 days with 5% HA. Increasing the proportion of HA improved interface formation; however, with high levels of HA, the PEG HA composite became brittle. This data suggests that HA, by itself or with other materials, might be well suited for engineering the ligament-bone interface.

Damage of collagen fibers in tendons is often directly related to changes in a tendon's mechanical properties. Direct quantitative elasticity measurement of tendons will provide important information in tendon dysfunction diagnosis and treatment assessment. A feasibility study of quantifying the mechanical properties of a degenerated tendon model by a nondestructive imaging modality, which combines optical coherence elastography and acoustic radiation force (ARF) method, is presented. The degenerated tendon model was produced by the partial degradation of chicken tendons through incubation with collagenase at different concentrations and incubation times. A 30-kHz longitudinal ultrasound transducer was used to provide an ARF signal, which was detected by an ultra-high sensitive phase sensitive optical coherence tomography (PhS-OCT) system. The experimental results demonstrate that the combination of ARF method and PhS-OCT can measure the elasticity of tendon quantitatively. The corresponding changes in tendon elasticity due to the application of collagenase have been revealed by this new imaging modality. This method can potentially be used in the assessment of tissue engineering products and in the diagnosis and treatment progression of tendon diseases.

Background: Catheter-associated urinary tract infections (CAUTIs) are among the most common hospital-acquired infections, leading to increased morbidity and mortality. A major reason for this is that urinary catheters are not yet capable of preventing CAUTIs. Aim: To develop an anti-infective urinary catheter. Methods: An efficient silver-polytetrafluoroethylene (Ag-PTFE) nanocomposite coating was deposited on whole silicone catheters, and two in-vitro bladder models were designed to test antibacterial (against Escherichia coli) and anti-encrustation (against Proteus mirabilis) performances. Each model was challenged with two different concentrations of bacterial suspension. Findings: Compared with uncoated catheters, coated catheters significantly inhibited bacterial migration and biofilm formation on the external catheter surfaces. The time to develop bacteriuria was an average of 1.8 days vs 4 days and 6 days vs 41 days when the urethral meatus was infected with 10 6 and 10 2 cells/mL, respectively. For antiencrustation tests, the coated catheter significantly resisted encrustation, although it did not strongly inhibit the increases in bacterial density and urinary pH. The time to blockage, which was found to be independent of the initial bacterial concentration in the bladder, was extended from 36.2AE1.1 h (uncoated) to 89.5AE3.54 h (coated) following bacterial contamination with 10 3 cells/mL in the bladder. Moreover, the coated catheter exhibited excellent biocompatibility with L929 fibroblast cells. Conclusion: Ag-PTFE coated Foley catheters should undergo further clinical trials to determine their ability to prevent CAUTIs during catheterization.